The bureau’s report was based on 28,000 comments from members of the public about private student loans. The contributors described their own difficulties and suggested ways to make student loan debt more manageable. The consumer agency analyzed the comments and highlighted some of the pros and cons in a report.

“Consumers told us how high monthly payments have left them trapped by their private student-loan debt,” Richard Cordray, the director of the consumer bureau, said in Miami at a hearing where he outlined the report. “They told us how this debt has forced them to sacrifice many of the features of middle-class American life.”

Cordray said the problems of student borrowers could have a domino effect on the economy, hurting housing, car sales and other sectors.

Private loans generally are riskier than federal student loans because they tend to have higher interest rates and come without flexible repayment schemes, such as income-based repayment. Some of those who commented told the consumer agency that they had to use large chunks of their incomes to repay their loans.

Many asked about refinancing. The rates are high when lenders are teenagers entering college, because there’s no guarantee they’ll get jobs. But even when they land jobs and dutifully make payments, many can’t find refinancing options, the report said.

Rohit Chopra, the consumer agency’s student loan ombudsman, said some smaller financial institutions had started to offer some refinancing but that the opportunities would have to be greatly increased to help more borrowers and make the market more efficient.

Other recommendations were for borrowers who got into trouble with payments. Suggestions included plans similar to the income-based options that are available with federal loans.

“Most borrowers aren’t looking to get off the hook,” Chopra said. “They just need a payment plan that works.”

The report looked at ways that the market and federal policymakers might be able to spur changes, including congressional action. For example, it said that if further study showed there wasn’t enough capital for a refinance market, lawmakers perhaps might authorize the use of the Federal Financing Bank, a government corporation.

Sen. Elizabeth Warren, D-Mass., introduced a bill Wednesday that would allow students to pay a much lower interest rate for one year. It would equal the rate that banks pay when they borrow from the Federal Reserve, about 0.75 percent. Warren said that would give Congress time to figure out a long-term plan on interest rates.